Chapter 6: Population Biology Flashcards
What is biotic potential?
The maximum reproductive rate of an organism; given unlimited resources and ideal environmental conditions.
What is a carrying capacity?
The number or biomass of a species that can be supported without depleting resources.
When food and resources deplete, what happens?
A population crash occurs.
What shape does an exponential growth rate model look like? Describe the model.
It has a J shape curve. This model describes when the population increases above the carrying capacity and suffers a population crash. The population decreases restarts the J shaped curve.
What is the shape of a logistic growth curve? What does the graph means.
It forms an S shape. The population of a community increases similar to a exponential curve, except when you reach the middle of the S, the rate of increase decreases and the population doesn’t exceed the carrying capacity.
Logistic growth is dependent on what factor?
Logistic growth is dependent on population density.
Name some examples of density independent factors.
Ususally abiotic factors like fires or drought.
What is an “r-selected” species? And what model discussed earlier can they relate to?
Employ a high reproductive rate to overcome the high mortality of offspring. (Housefly) These species can relate to the exponential model.
What is a “K-selected” species? And what model discussed earlier can they relate to.
Reproduce conservatively with longer generation times and fewer young. (Humans) These species can relate to the logistic growth model.
What is the equation for the rate of growth?
(B+I) – (D+E) = rate of growth; B = Births, D = Deaths, I = immigrants, E = emigrants
What is Total Fertility Rate?
Average number of offspring born to a female in her lifetime.
What is Replacement-Level Fertility?
Average number of offspring a mating pair must bear to replace themselves in a population. (Slightly over 2 per couple)
What is Mortality?
Death Rate
What is Natility?
Birth Rate
How many types of survivorship are there? What are they?
There are 3 types of survivorship. The first is where organisms have a high juvenile survival rate and tend to reach old age. The second is where the probability of death is unrelated to age. The third is where organisms are very susceptible to death early in life, but if they make it to adulthood, they will probably live to the maximum life span.
What are Intrinsic factors?
Factors from within a single population
What are Extrinsic factors?
Imposed from outside the population
What are Biotic factors?
Caused by living organisms; tend to be density dependent (effects are stronger when population density increases)
What are Abiotc factors?
Caused by environmental or non-living components; tend to be density independent (effects are the same regardless of population density)
Name some interspecific interactions.
Predator-Prey relationships, mutualism, commensalism
Predator Prey relationships are always bad for the prey species. True or False. Explain.
False. Example: A moose population can be strengthened because the old and sick moose will be eaten by the wolves, and the healthy and young moose will survive and reproduce.
Name some intraspecific interactions.
Territoriality.
What is Territoriality?
Fighting to prove resources belong to a particular individual in a population. Territorial displays are often linked to mating rituals (dancing or singing ability, best colors, etc.). It is also related to fighting equipment (teeth, claws, antlers, horns, etc.)
What are Stress-Related diseases (stress shock)?
Due to too much competition for resources or limited living space. This leads to lower fertility, less disease resistance, and pathological behavior.
What is Island Biogeography?
The study of rates of colonization and extinction of species on islands or isolated areas based on size, shape, and distance from other inhabited regions. *Note: Biodiversity increases with an increase in island size and closeness to mainland
What is Genetic Drift?
Gradual changes in gene frequencies due to random events.
What is the Founder Effect?
(demographic bottleneck) - a few members of a species survive a catastrophic event or colonize a new habitat geographically isolated from members of the same species.
What is Minimum Viable Population Size?
Number of individuals needed for longterm survival of a rare or endangered species. Example: for the grizzly bears the minimum viable population size is 100 bears.
What is Metapopulation?
A population of populations that have regular or irregular gene flow between geographically separated units. Example: Butterfly patches in different locations.
